Zhao et al. (2026) Effects of sprinkler irrigation intensity with brackish water on water–salt transport in the soil profile and yield of winter wheat: A field experiment and HYDRUS-1D simulation

Identification

• Journal: Agricultural Water Management
• Year: 2026
• Date: 2026-11-04
• Authors: XiLin Zhao, Yue Qiang Jiang, Luya Wang, Run Xue, Pan Tang, liyuan zhang, Vesna Milić, Bоris Pаšаlić
• DOI: 10.1016/j.agwat.2026.110923

Research Groups

• School of Agricultural Engineering, Jiangsu University, Zhenjiang, China
• Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang, China
• Faculty of Agriculture, University of East Sarajevo, East Sarajevo, Republic of Srpska, Bosnia and Herzegovina
• Faculty of Agriculture, University of Banja Luka, Banja Luka, Bosnia and Herzegovina

Short Summary

This study investigated the effects of sprinkler irrigation intensity on soil water-salt transport and winter wheat yield under brackish-water irrigation using field experiments and HYDRUS-1D simulations. It identified optimal irrigation intensities (1.33 × 10⁻⁶ m s⁻¹ for 3 kg m⁻³ salinity; 1.33 × 10⁻⁶ m s⁻¹ and 1.81 × 10⁻⁶ m s⁻¹ for 5 kg m⁻³ salinity) that balanced water-salt dynamics and minimized yield reduction.

Objective

• To determine the effects of irrigation water salinity and sprinkler irrigation intensity on soil water-salt distribution and dynamic transport in winter wheat.
• To simulate and explain soil water-salt dynamics under various sprinkler irrigation intensities.
• To evaluate winter wheat yield and its components' responses to different salinity levels and sprinkler irrigation intensities, thereby providing a basis for optimizing brackish-water sprinkler irrigation for winter wheat in semi-arid regions.

Study Configuration

• Spatial Scale: Field experiment conducted at Wangdu Irrigation Experimental Station, Baoding, Hebei Province, China (38°42′ N, 115°06′ E; elevation 51.0 m). Soil profile depth of 1.0 m was studied, with measurements at 0-0.1 m, 0.1-0.2 m, 0.2-0.3 m, 0.3-0.4 m, 0.4-0.6 m, 0.6-0.8 m, and 0.8-1.0 m. Yield was harvested from 1 m² quadrats. Sprinkler spacing ranged from 8.3 m to 9.5 m.
• Temporal Scale: Winter wheat growing season from 11 October 2024 to 13 June 2025. HYDRUS-1D simulations covered 1.48 × 10⁷ seconds (172 days) from 26 November 2024 to 16 May 2025. Irrigation events occurred on 28 November 2024, 15 March 2025, and 12 May 2025.

Methodology and Data

• Models used: HYDRUS-1D (for one-dimensional soil water movement, solute transport, and root water uptake), van Genuchten–Mualem model (for soil hydraulic properties), Feddes model (for root water uptake).
• Data sources:
  • Field experiment: Soil water content (volumetric, m³ m⁻³), soil electrical conductivity (EC, S m⁻¹), winter wheat yield (kg m⁻²) and yield components (effective spikes per unit area, grains per spike, 1000-grain mass, spike length).
  • Irrigation water: Two salinity levels (3 kg m⁻³ and 5 kg m⁻³) prepared by adding sea salt to deep groundwater (0.21 kg m⁻³ salinity). Each irrigation event applied 0.018 m of brackish water followed by 0.018 m of freshwater.
  • Sprinkler characteristics: Five sprinkler irrigation intensities (5.0 × 10⁻⁷ m s⁻¹, 8.9 × 10⁻⁷ m s⁻¹, 1.3 × 10⁻⁶ m s⁻¹, 1.8 × 10⁻⁶ m s⁻¹, and 2.3 × 10⁻⁶ m s⁻¹) generated by adjusting sprinkler type, nozzle configuration, and operating pressure. Droplet diameter, velocity, kinetic energy per unit volume, Christiansen uniformity coefficient (CU), and lower-quarter distribution uniformity coefficient (DU) were measured.
  • Soil physical properties: Particle-size distribution, bulk density (mean 1580 kg m⁻³), organic matter content (0.7%), and van Genuchten (VG) parameters predicted using the Rosetta pedotransfer function.
  • Meteorological data: Daily precipitation, relative humidity, maximum and minimum air temperatures from Wangdu Meteorological Station No. 54607 (mean annual temperature 12.5 °C, mean annual precipitation 0.4954 m).

Main Results

• Soil water content and electrical conductivity (EC) were significantly affected by irrigation water salinity, sprinkler irrigation intensity, growth stage, and soil depth, with treatment differences mainly concentrated in the 0-0.4 m soil layer.
• HYDRUS-1D simulations adequately reproduced soil water-salt dynamics, with correlation coefficients (R) ranging from 0.78 to 0.89 and Nash–Sutcliffe efficiency (NSE) values from 0.48 to 0.75.
• Under 3 kg m⁻³ brackish water, increasing sprinkler irrigation intensity from 5.0 × 10⁻⁷ m s⁻¹ to 2.3 × 10⁻⁶ m s⁻¹ generally decreased mean cumulative net infiltration during irrigation (from 0.03505 m to 0.02408 m) and cumulative net downward water and salt transport across the 0.4 m soil-depth interface.
• Soil water and salinity responses to sprinkler irrigation showed a delayed peak with increasing soil depth; salinity response lagged later than soil water. Shallow salt accumulation was more pronounced at 5.0 × 10⁻⁷ m s⁻¹, whereas shallow-soil EC was relatively low at 1.3 × 10⁻⁶ m s⁻¹ and 1.8 × 10⁻⁶ m s⁻¹ at some growth stages.
• Increasing irrigation water salinity from 3 kg m⁻³ to 5 kg m⁻³ further increased soil salt accumulation and expanded the affected soil depth.
• Under 3 kg m⁻³ salinity, a sprinkler irrigation intensity of 1.3 × 10⁻⁶ m s⁻¹ resulted in a winter wheat yield of 0.988634 kg m⁻², which did not differ significantly from the freshwater control.
• Under 5 kg m⁻³ salinity, yield reductions were minimized at 1.3 × 10⁻⁶ m s⁻¹ (7.08% reduction) and 1.8 × 10⁻⁶ m s⁻¹ (5.55% reduction) compared to other intensities, though still significantly lower than the control.

Contributions

• Clarified the independent effects of sprinkler irrigation intensity (water input flux and irrigation duration) on water retention, salt migration depth, and winter wheat yield under an equal irrigation amount, addressing a gap in existing literature.
• Integrated field observations with HYDRUS-1D simulations to provide a continuous and comprehensive understanding of water infiltration, salt transport, and root water uptake dynamics, overcoming limitations of intermittent field sampling.
• Provided a practical basis for optimizing brackish-water sprinkler irrigation for winter wheat in semi-arid regions by identifying specific optimal intensities for different salinity levels.
• Demonstrated that the optimal irrigation intensity is dependent on irrigation water salinity, highlighting the need for tailored management strategies to mitigate yield loss under varying brackish water qualities.

Funding

• National Key Research and Development Program of China, grant numbers 2023YFD1900804–01, 2023YFD1900804–02, and 2025YFE0211700.

Citation

@article{Zhao2026Effects,
  author = {Zhao, XiLin and Jiang, Yue Qiang and Wang, Luya and Xue, Run and Tang, Pan and zhang, liyuan and Milić, Vesna and Pаšаlić, Bоris},
  title = {Effects of sprinkler irrigation intensity with brackish water on water–salt transport in the soil profile and yield of winter wheat: A field experiment and HYDRUS-1D simulation},
  journal = {Agricultural Water Management},
  year = {2026},
  doi = {10.1016/j.agwat.2026.110923},
  url = {https://doi.org/10.1016/j.agwat.2026.110923}
}